| Rescue Knives | | | | opens the blade. If the knife is drawn out |
| | | | and backwards in one complete motion, the |
| Blade Style | | | | blade opens fully to the locked open |
| | | | position. |
| Rescue Knife designs often feature a | | | | |
| modified Sheep Foot or Wharncliffe style | | | | Another option is the thumb stud, which can |
| blade. Emergency procedures may involve | | | | be right or left handed or ambidextrous. |
| cutting through a jammed seat belt in the | | | | This may be permanently riveted to the blade |
| aftermath of a car crash. Clothing may also | | | | as most ambidextrous thumb studs are, or |
| have to be cut through in order to free a | | | | removable to allow for right or left handed |
| victim or to gain venous access. Cutting | | | | positioning. The so-called ambidextrous thumb |
| through fibrous materials in such close | | | | lug is attached to the back edge of the blade |
| proximity to the casualty is much safer if | | | | instead of the flat surface of the blade. The |
| the knife being used has a blunt or rounded | | | | disadvantage of having a thumb stud or lug |
| tip. | | | | attached to the blade is that it may |
| | | | interfere with the cutting activity when |
| The Emerson Knives US Navy Search and Rescue | | | | using the knife. If the thumb stud is |
| Knife (SARK) has a partially serrated blade | | | | positioned too far along the blade it will |
| with a Wharncliffe style blade, similar to | | | | compromise the blades usefulness, whilst if |
| the Eickhorn Pocket Rescue Tool PRT XII. The | | | | positioned too close to the handle, it will |
| Spyderco Atlantic Salt and Rescue 93 mm | | | | be difficult in practical use. |
| knives are blunt-ended Sheep Foot style | | | | |
| blades | | | | The blade opening, thumb hole-pull also |
| | | | allows one-handed opening. The cut-out |
| A serrated edge increases the effective | | | | portions of the blade are different shapes |
| cutting edge length by up to 24%. The | | | | depending on the manufacturer. There are many |
| sharpened recesssed curve has more linear | | | | variations such as the Spyderco Round Hole, |
| cutting surface than a straight edge. Edge | | | | the Tool Logic oval hole, the Byrd Knives, |
| retention is also greater because cutting is | | | | tear-drop shaped hole and the Leatherman |
| started by the serrations' tips, easing the | | | | oblong shaped thumb hole pull. The size of |
| workload on the recessed edges, and | | | | the thumb opening hole in Spyderco knives is |
| protecting the sharp inside cutting curves | | | | increased to 14 mm diameter in military and |
| which wear less over time. | | | | rescue models, an allowance for gloved |
| | | | hand-use. Thumb hole sizes in Spyderco knives |
| Seat Belt Cutter | | | | varies from 11 mm in the Lava and Kopa |
| | | | knives, 12 mm in the Police knife, 13 mm in |
| A Secondary blade or seat belt cutter is a | | | | the UK Penknife and 14 mm. In the Assist and |
| safety feature for use when cutting in close | | | | Atlantic Salt knives. The Spyderco Assist |
| proximity to a living person. This may | | | | Knife has an added 'Cobra Hood', which is a |
| involve cutting through a jammed seat belt | | | | raised border along the top edge of the spine |
| restraint or cutting through clothing. | | | | cusp above the thumb hole. The 'Cobra Hood' |
| Incorporated into a slot in the handle it is | | | | makes blade opening easier when the thumb is |
| used by positioning the fixed material within | | | | not fully engaged in the thumb hole, for |
| the slot and pulling the knife in the | | | | instance when the user is wearing gloves. |
| opposite direction. | | | | |
| | | | Holding the knife in the palm of the hand at |
| The 'Rescue Hook' is a design variation where | | | | the base of the fingers, grasp the handle |
| the blade tip has a blunt outer surface, and | | | | with the tips of the fingers, place the pad |
| a sharpened inner crescent shaped edge. Many | | | | of the thumb in the thumb hole, then slide |
| manufacturers have their own variants of this | | | | the blade away from the handle using the |
| design. An example is the Eickhorn Pocket | | | | thumb. |
| rescue Tool PRT XI | | | | |
| | | | Window Puncher / Glass Breaker |
| One-Handed Opening | | | | |
| | | | The window puncher or glass breaking stud is |
| The Emerson wave Hook, invented by Emerson | | | | a pointed, cylindrical protrusion mounted on |
| Knives provides a solution to the one-handed | | | | the handle, usually at the opposite end to |
| opening of a folding knife. This opens the | | | | the blade pivot. It is made of tungsten |
| blade when the knife is withdrawn from a | | | | carbide, effective at breaking toughened |
| pocket. Grasping the end of the handle | | | | glass due to its diamond-hard nature. The |
| between forefinger and thumb, the knife is | | | | Spyderco Assist knife has a retractable |
| drawn out and backwards. The hook protruding | | | | carbide tip, which is activated by squeezing |
| from the blade back catches on the pocket and | | | | the blade into the handle. |